According to researches, in addition to causes such as age and heredity, unhealthy and even incorrect use of eyes is the main cause of a vision decline. For example, eyes are used for a long time, at a short distance, and the like. Besides the vision decline, in some scenarios, incorrect use of eyes may result in extremely severe consequences. For example, in a driving state, if a driver fails to concentrate and gazes in an incorrect direction, a traffic accident may occur, causing a great threat to personal safety.
To protect vision and urge correct use of eyes, there is a method of measuring a distance from eyes to an object in front of a user and sending an alert when the distance is inappropriate. The method may have a desirable effect of reminding a user in a certain application scenario such as reading and writing. However, in the method, as a distance between eyes and an object in front is measured, and the object is not necessarily a position at which a user actually gazes, the application range of the method is limited and a false alert may be sent in a specific scenario.